Ok so i placed a thread on here a couple of weeks ago about my car making a tapping noise after 4000rpm, people said check my oil so i did and it was fine and brand new pretty much, since then i have been told my car is "pinking" ( air and fuel mixture is wrong) so i was advised to put a higher octane fuel in, so i did, no difference, yesterday my EGR valve went and i was told this would fix the problem... it hasnt!
had all gaskets checked on my manifold / exhaust, all fine.
What else could the tapping possibly be :S only appears after 4000rpm when accelerating, stops when foot is taken off the gas.
Could it be my hydraulic tappets not filling with oil or anything like that??